Each report is produced by a committee of experts selected
by the Academy to address a particular statement of task and
is subject to a rigorous, independent peer review; while the
reports represent views of the committee, they also are
endorsed by the Academy.
Learn more on our expert consensus reports.

Protecting buildings and their occupants from biological and chemical attacks to ensure continuous building operations is seen as an urgent need in the Department of Defense, given recent technological advances and the changing threats. Toward this end, the Department of Defense established the Immune Building Program to develop protective systems to deter biological and chemical attacks on military facilities and minimize the impacts of attacks should they occur. At the request of the Defense Threat Reduction Agency, the National Research Council convened a committee to provide guiding principles for protecting buildings from airborne biological or chemical threat agents and outline the variables and options to consider in designing building protection systems. This report addresses such components of building protection as building design and planning strategies; heating, ventilating, and air-conditioning systems; filtration; threat detection and identification technologies; and operational responses. It recommends that building protection systems be designed to accommodate changing building conditions, new technologies, and emerging threats. Although the report's focus is on protection of military facilities, the guiding principles it offers are applicable to protection of public facilities as well.

Key Messages

A systematic process that takes into account the building's vulnerabilities and risks of attacks, its physical limitations, the budget, and options for protection using risk assessment and management approaches is needed to guide decision making and cost-benefit analysis for building protection.

Building protection systems cannot be standardized or even generalized because the physical characteristics of buildings their age, quality of construction, leakiness and ongoing activities inside vary greatly within and across military and civilian sectors.

Building use, with respect to its contents or occupants and their activities and mission, should play a large role in determining the type and level of protection needed.

Level of protection 1 (LP-1) is a low-level passive protection that has no sensors or additional options installed specifically to address biological and chemical threat agents.

Level of protection 2 (LP-2) is a high-level passive protection that does not utilize sensors.

Level of protection 3 (LP-3) is a low-level active protection designed to detect and identify threat agents in time to execute therapeutic responses, but not quickly enough to warn occupants of the threat before exposure occurs.

Level of protection 4 (LP-4) is a high-level active protection that can detect and identify a threat agent in time to mitigate the release. LP-4 can detect a threat early enough to make operational responses that prevent exposure, such as redirecting ventilation or donning personal protective equipment.

The best classification of threat agents is according to the two most critical properties related to current vulnerabilities in building protection the ease of timely detection and the ease of timely treatment. This classification treats biological and chemical threats equally and addresses vulnerabilities from unknown threats.

The committee defined four levels of protection (LPs) that are not absolute but can be used to illustrate the components needed and options available for achieving desired protection goals. These levels of protection are qualitative, like the biosafety levels of microbiological and biomedical laboratories.

There is no universal set of metrics that can be used to assess protection systems of all buildings because of the uniqueness of each building, its use, and the goals and objectives of its protection.